The rate of synthesis of individual ribosomal proteins will be measured in oocytes of Xenopus laevis and in the ciliated protozoan Tetrahymena pyriformis. This will be done to determine whether ribosomal proteins in these cells are coordinately synthesized relative to each other. Under conditions which promote either increased or decreased rates of ribosome production similar measurements will be made to see if coordination is maintained during a shift from one state to another. In addition the overall rates of ribosomal protein synthesis and ribosomal RNA synthesis will be compared to see whether their syntheses are coordinate as well. Characterization of conditional temperature sensitive mutants of Tetrahymena unable to synthesize new ribosomes will be continued. These mutants will be used in an attempt to dissect the pathway of assembly of new ribosomes.